                        |
|
When polled on the
question, "How many in the audience have fuel odors in their
C1?", the count was in the 80 percentile. The remaining 20
% may not drive their cars. This is a common issue as the
fuel tank is located in close proximity to the passenger
compartment. The fuel tank is reached by opening the cover
behind the seat and lifting the soft-top out (if you have one)
and removing the fiberglass panel exposed when the top is
rotated up out of the cavity. Removing the panel is
accomplished by removing all the screws around the panel and
lifting the panel out. In some C1's the seats may have to
be removed, loosened or just slid forward. Personally
(webmaster), I can get access to the screws by just removing the
back cushions on my '60.
Chip Werstein did a great
job discussing the aspects/sources which must be addressed on
the fuel tanks to eliminate odors. First, obtain all the
listed items when attacking the fuel odor problem prior to
beginning this "restoration" and you can most-likely complete
the entire task in a day. If you don't obtain the items,
you will spend a lot of time looking for parts and your car will
be down the whole duration. |
 |
|
Above, Chip addresses the
fuel tank issues while sitting alongside on the table is a C1 fuel
tank.
For this write up on Chip's subject, your webmaster
has taken pictures of his car as an example to further explain
the issues discussed. Also, since I have replaced several
of these components some editorial liberty's were added. |
|
Pre-Purchased Items:
(Note: Webmaster has listed
part numbers from Corvette Central (CC) only because I had a
CC catalog in front of me. Many of these parts are the same
from other vendors. At least you can find what they look
like in CC's catalog)
1. Tank Vent Rubber Tubing,
57 to 62, CC#361114, approx $9, (if purchased locally, always use
gasoline rated rubber)
2. Fuel Filler Tube (hose
clamps might be optional, many times these are reuseable), CC
#361112 tube w/clamps, approx. $20.
3. Fuel Sending Unit gasket
(cork preferred, rubber will creep/flow when clamped), CC lists
a gasket but I am not sure of the material, CC #361109
approx. $5.
4. Fuel Filler Tube Grommet
(located and visible in filler compartment), 53 to 62,
CC#361113, approx $9
5. Tube for
venting/draining Fuel Filler Compartment, 56 to 62,
CC#361020, approx. $5
6. 10-32 Screws for
fastening fiberglass panel in soft top compartment, purchase at
Home Depot.
7. J-Nut and screws for
rear part of fiberglass panel in soft top compartment (CC screw
set (56 to 61) #341110, (61L to 62 #341111).
8. Sealing Strips for placing between panel and body when installing
tank fiberglass panel
(CC Strip Caulk, 53 to 62, #281125), approx. $8.
9. Fuel sending unit pickup
strainer, 53 to 62, CC #362209, approx. $10
Optional Items, if interested &
YOU MAY NEED them:
1. Steel Gas Tank, 57 to
62, vented, CC #361004 $220 (Personal experience locally, it
cost approx. $200 to have your gas tank renewed).
2. Gas Tank Fiberglass
Cover, 56 to 62, CC #361003 approx. $140.
3. Fuel level Sending Unit,
56 to 61E, CC #361107, 61L to 62, CC #361108, approx $70
4. Fuel filler neck
(Metal), CC 55 to 60, #361015, 61 to 62, CC#361016, approx $50 |
|
 |
|
The picture above is the
entire fuel tank after removing the panel cover. This is a
'60 car and panel screw access was available by removing the
seat back cushion and moving the frame forward (normal sliding
adjustment).
The forward screws are 10-32 machine screws while the ends and
the rear screws are J-nuts with associated screws. Visible
at this point is the fuel level sending unit, fuel tank vent
line, one end of the fuel filler tube (w/clamp), fuel sending
unit electrical wires and the fuel supply line exiting the top of
the photo. The remaining black wire crossing the tank was
for my CB radio. |
 |
|
Above is the fuel filler
hose with one clamp that attaches the filler to the tank.
This clamp can be tightened while the one hidden at the other
end of the hose is near impossible. |
 |
|
Opposite of the
filler end of the tank is the fuel level sending unit and it can
be seen that the fuel supply line to the engine exits on the
passenger side of the car. Note the stains from past fuel
leaks, or seeping from the sending unit. To the rear of
the tank a bolt head is visible. This bolt (one of four)
secures two straps which hold the tank in position in the car. |
 |
|
A closer view of the
sending unit from the passenger side of the car. Note that the fuel
supply tube extends and is part of the sending unit.
Inside the tank, this tube has a screen (not visible unless you
remove sending unit) slipped over to prevent particulates from
entering the fuel line. If your fuel level gage is
inoperable or inaccurate you might consider replacing the sending
unit at this time. Save the mounting screws
(hex head flanged) and replace if in good condition.
Sometimes slotted or Philips screws come with the replacement but
the hex head is correct and easier to tighten.
Another item, from the
above picture, is the electrical wires attach to the center of
the sending unit (from fuel gage) and a ground which attaches to
a mounting screw. The tapped holes mounting the sending
unit are "thru" holes, i.e., the screws must be sealed or fuel
will seep/wick up and you will have a fuel odor. Small o
rings sometimes come with the sending unit and some installers
put a small amount of Form A Gasket on the screw threads when
installing.
The Corvette vent tube
connection is a slip fit and pressure clamp. This is the
tube which extends over to the drivers side fuel filler compartment.
The fuel supply line is
connected to the line exiting the tank area (note rubber under
supply line to prevent vibration noise) to under your car and
forward toward the engine along the frame. The picture
below shows the fuel line as viewed forward of the rear
passenger wheel. As is obvious, there is another
fuel line connection visible and the fuel line is protected from damage
with a outer "spring-type" wrap. This prevents damage from
flying debris near the rear wheel. |
 |
  |
|
The above picture is the
gas filler door area. Cars that are pre-61 have doors that
open vertically while the '61 and '62 are hinged on the left
side. Another difference is the end of the vent tube (from
the gas tank vent) on the '61 and '62 extends horizontally from
the hole above and travels over toward the hinged area of the
door. The correct gas filler caps after 1956 were sealed caps and not
vented (the tank is vented). Non vented caps are
difficult/expensive to locate and clearly I have the wrong one.
After 1956 the tanks were
vented negating the use of a vented cap. CC does sell a 53
to 62 (replacement cap) with Anti-surge Venting. The black area
around the filler neck is a grommet which is listed in the parts
list above. If the filler neck tube is replaced, the
grommet might as well be replaced. Other items on the list
are the vent hose and its associated grommet.
When the gas cap is
removed, inspect the surface of the filler neck for damage (this
part can be replaced also and is listed above) and make certain that the cap rubber
gasket is good and the cap tightens down tight. The rubber
fuel door bumpers can be replaced/installed at any interval. |
Another item to inspect and
many do not know this exists (including me), is the vent hole located below the
gas cap. This vent hole is not very visible in the upper
pictures but the hole will allow spillage to drain out of the
compartment. A rubber tube slips on the nipple/protrusion on the
underside and extends down and under the car. Otherwise
the spillage will drip into the passenger compartment.
Sometimes the gas cap
blocks the view of this hole, but it is there. |
|
Webmaster Testimonial:
I determined that the
rubber drain tube was missing which drained the spillage out of
the gas filler area in my '60 so I set out to install a drain.
I did this task without removing or loosening the tank. It
does make it more difficult and it helps if you have skinny
arms. 1. I
removed the gas tank fiberglass cover from the soft-top
compartment. This exposed the fuel tank filler rubber
connection between the filler pipe and the fuel tank.
Loosen the clamp attaching the tube to the tank. The
remaining clamp usually cannot be seen or accessed.
2. Remove the gas cap.
Remove the filler tube grommet. If you have a replacement
this is simple, cut it. I wanted to save mine and squirted
WD-40 on it and this makes is slide on the tube. Once the
grommet is pliable and rotates, slid it off or rotates
sufficiently to remove it. Rotate the filler neck and
disconnect the rubber tube connecting the filler tube to the
tank. WD-40 and a prying screwdriver can assist here also.
I also wanted to save this tube so I was careful.
3. Removing the filler
tube through the hole in the gas filler area is usually not
possible because of the size of the head on the remaining clamp.
I pushed the filler assembly down into the cavity next to the
tank and removed the remaining clamp. The whole assembly
is easily removed through the filler area hole when this is
done.
4. Slip the rubber drain
hose over the nipple of the hole for draining gas
spillage. With the gas tank installed this is not easy to
get you hand underneath to push the tube on. I believe,
there is a sharp protrusion on this nipple which assists in
retaining the tube once slipped over the nipple. Again,
WD-40 helps slide the tube on. Make sure the tube is long
enough to extend through a hole underneath the tank area and
allow the spilled fuel to drain out.
5. Reversing the above
order of assembly will complete the job. When installing
the fuel filler tube assembly, make sure the hose clamp on the
filler tube side is tightened prior to slipping the tube on the
gas tank because the inner clamp is not accessible.
 Leaving
the grommet off while assembling the filler tube also makes the
process easier. This grommet (with a WD-40 application)
will slip over the gas cap end of the tube. Reinstall the
gas tank cover as outlined above. |
|
Chip's Recommended Fuel Odor Elimination Procedure:
It is recommended that you
perform this procedure with as little fuel in the tank as
possible.
1. Preparation: Purchase the parts list
identified at the beginning of this article. Some of the
visible items (gas filler cap surface, gas filler metal tube,
gas cap and others can be inspected prior to parts purchasing).
If fuel gage is operating correctly, you may not need to
purchase a new fuel level sending unit, however, do obtain a new sending unit cork
gasket. You might want to also purchase the screen for the
sending unit pick up as they do deteriorate. You will most
likely pull the sending unit whether you use your existing or
purchase a new one.
2. Begin by removing the fiberglass
panel in the bottom of the storage compartment (behind the seats).
Clean any sealant existing on mating surface between panel and
car body. |
|
3. Inspect areas discussed
earlier (fuel supply line, sending unit mounting surface, fuel
filler tube connection) for obvious fuel leaks/seepage. |
|
4. Spray some type of rust
remover lubricant on the gas tank hold down straps bolt threads that are securing the fuel
tank. Let sit for a comfortable duration where you feel
comfortable in removing/loosening these bolts. Don't force
the removal, the fix to the fixed nuts is a Big Job! |
|
5. Remove/Loosen the
exposed clamp on the gas filler tube shown above. In order
to separate the filler tube and tank, the hold-down straps
should be loosened and the tank moved toward the passenger side
of the car. The fuel supply line on the tank top must be
disconnected in order to "move not remove" the tank. Hint:
Use a board on the drivers side to "pry/nudge" the tank over to
disconnect the fuel filler tube. Remove the gas filler metal
neck, grommet and tube separating it from the gas
tank (the remaining clamp will most likely hold this assembly
together). These parts should come out through the gas filler
door compartment. |
|
6. Remove the electrical
connection at the center of the sending unit. Remove the
screws securing the sending unit to the tank (one screw contains
the ground wire). Remove the sending unit.
Turn each screw slowly and spray
rust remover in necessary so a NOT TO TWIST OFF A SCREW.
Another fix you don't want to do. |
|
7. Inspect the sending unit
float, corrosion under the sending unit, and the screen at the
end of the filler tube. This is the decision stage to
decide on installing a new sending unit unless you already
purchased a unit. Clean the
mounting surfaces of the sending unit and tank. Avoid
particles from dropping into the tank. |
|
8. Using a flashlight
inspect the inside of the tank. Decision Point: If
cleaning the tank is needed, it can be removed and brought to a fuel tank restoration/radiator shop to be
boiled out. Depending on the amount of contamination
and/or damage, reproduction tanks are available (see list above). |
|
8. Tank removal requires
removing the hold-down straps.
9. Install the vent tube
which extends from the gas filler compartment and properly route
it under the car.
10. Relocate the tank back into
its proper location and tighten the hold-down straps.
|
|
11. Sending unit reassembly:
Prior to
inserting the sending unit into the tank top, "chase" out the
threads used to mount the tank. Sometimes these holes are
gooped with sealant and installing these small screws cannot
take a lot of torque. Take care to capture any
particles by placing you hand or something inside the tank under the
screw hole being chased. Insert the sending unit containing a good
screen into the tank. Don't forget to slip the new cork
mounting gasket on first. Using a light coating on both
surfaces of the gasket set the sending unit on the tank surface
and install a screw (temporary). This will secure the unit
while checking that all the screw holes line up. Continue
to install the mounting screws remembering to put on the small
rubber seals on each screw and some thread sealant on the
threads. |
|
12. Tighten the sending
unit screws using a nut-driver for hex head screws.
Remember to locate the grounding lug underneath the correct
mounting screw. Place the fuel gage electrical wire on the
center of the sending unit. Reconnect the engine fuel
supply line. |
|
13. Install a new rubber
vent line by slipping tube over the fuel tank vent and install
clamp. Route this vent line over toward the gas filler
compartment and "properly" insert it through the body with a
grommet. |
|
14. Assemble the New/Old
metal filler neck and new filler neck tube (on the work bench) and tighten the metal
clamp. Remember that this clamp has no access when
installed. Slip grommet over the filler neck. Feed
the filler assembly through from the outside of the filler
compartment down to the tank. Prior to slipping the filler
tube on the tank, install the tank side tube clamp, loosely.
After slipping the filler tube on tank, tighten the clamp. |
|
15.Prepare to install the
upper fiberglass tank cover panel. Chase the threads on
all 10-32 captured screws and install J-nuts where used. |
|
Chip Says,
"IF you do this process properly, as
outlined, and carefully, you should not have gas odors". |
|
|
